Observation of the topological Anderson insulator in disordered atomic wires

TL;DR

This paper experimentally demonstrates the topological Anderson insulator phase in disordered atomic wires, showing how disorder can induce topological properties in a quantum system, with implications for future strongly interacting topological states.

Contribution

First experimental realization of topological Anderson insulator in ultracold atomic wires using spectroscopic Hamiltonian engineering and quench dynamics measurement.

Findings

Evidence for topological Anderson insulator phase

Robustness of topological phase to weak disorder

Transition to trivial phase under strong disorder

Abstract

Topology and disorder have deep connections and a rich combined influence on quantum transport. In order to probe these connections, we synthesized one-dimensional chiral symmetric wires with controllable disorder via spectroscopic Hamiltonian engineering, based on the laser-driven coupling of discrete momentum states of ultracold atoms. We characterize the system's topology through measurement of the mean chiral displacement of the bulk density extracted from quench dynamics. We find evidence for the topological Anderson insulator phase, in which the band structure of an otherwise trivial wire is driven topological by the presence of added disorder. In addition, we observed the robustness of topological wires to weak disorder and measured the transition to a trivial phase in the presence of strong disorder. Atomic interactions in this quantum simulation platform will enable future realizations of strongly interacting topological fluids.